Technologies related to this type of fuel cell include what is disclosed in Patent Literature 1, titled a “membrane-electrode assembly.”
The membrane-electrode assembly disclosed in Patent Literature 1 includes a membrane-membrane reinforcing member assembly, an anode catalyst layer (or a first catalyst layer), a cathode catalyst layer (or a second catalyst layer), an anode gas diffusion layer (or a first gas diffusion layer), and a cathode gas diffusion layer (or a second gas diffusion layer).
The membrane-membrane reinforcing member assembly includes a polymer electrolyte membrane, one or more flaky first membrane reinforcing members disposed on top of a principal surface of the polymer electrolyte membrane in such a way as to extend along the periphery of the polymer electrolyte membrane as a whole, and one or more flaky second membrane reinforcing members disposed on top of the first membrane reinforcing member in such a way as to extend along the periphery of the polymer electrolyte membrane as a whole and to have its inner periphery shifted from the inner periphery of the first membrane reinforcing member, as seen from a thickness direction of the polymer electrolyte membrane. Incidentally, the first membrane reinforcing member and the second membrane reinforcing member are mainly made of synthetic resin.
The anode catalyst layer is formed to cover the principal surface of the polymer electrolyte membrane while filling in an opening formed in the first membrane reinforcing member, and likewise, the cathode catalyst layer is formed to cover the principal surface of the polymer electrolyte membrane. The anode gas diffusion layer is disposed to cover the anode catalyst layer and a portion of a principal surface of the first membrane reinforcing member, and the cathode gas diffusion layer is disposed to cover the cathode catalyst layer and a portion of the principal surface of the first membrane reinforcing member.
The above-described configuration is intended to increase durability by preventing damage to the polymer electrolyte membrane by contact with an end portion of the gas diffusion layer, and by more reliably suppressing damage to the polymer electrolyte membrane by an end portion of the first membrane reinforcing member.